1. Field of the Invention
The present invention relates to a method for producing a porous carbon material product and a hard porous carbon material product utilizing bran such as rice bran or wheat bran as a raw material. The bran has been less usable and has not been treated as industrial resources.
2. Description of the Related Art
A large amount of chaff rice hulls and chaff is generated as by-products from rice which is a main crop in Japan. Similarly, a large amount of chaff and wheat bran is derived from the crops such as wheat, buckwheat or soybeans. Many of the by-products such as the chaff or the bran derived from the crops are tend to be burned as wastes. However, rice bran is oil-pressed to produce rice bran oil. In addition, the chaff (especially chaff rice hulls) are utilized only partially for a culvert and smoking charcoal, and dry distilled substances distilled during the production process of the smoking charcoal are condensed to be used for an insecticide, an animal repellent, a soil conditioner, a remedy for deematophytosis or the like.
However, most of the bran including defatted bran is merely utilized for agricultural materials such as feed, fungus culture medium or manure. Accordingly, effective utilization of the bran as industrial materials has been investigated.
One utilization is a technology that the bran is carbonized. The carbonization of the bran is implemented by steam baking the bran in a batch on a small scale, or by burning successively in a rotary kiln, multistage fluidized bed furnace or the like on a large scale. However, the bran is very fine powder and have less permeability and thermal conductivity. In addition, oil and fat is included therein a large portion, although an amount thereof is small. Therefore, the bran may be burned out and incinerated. Thus, effective and complete carbonization is difficult, which induce lower economic efficiency. Moreover, obtained carbide is fine and easy to splash, and thus is inconvenient for treating. The above problems prevent positive industrialization. Consequently, the carbide, so-called "charcoal," produced from the bran is utilized as a agricultural soil conditioner, but is not utilized as industrial materials due to its quality and quantity.